Dan Wheat/Capital Press
Blas Plazo operates tractor cutting tops of 20-foot-tall vines from trellises that fall into the bed of a truck the tractor is pushing. About 150 vines fill a truck.

Dan Wheat/Capital Press
Oils inside the cones are extracted for flavoring and stabilization in brewing beer.

Hop trucks clutter roads in Washington's Yakima Valley in September. The valley and regions in Oregon and Idaho make up U.S. hop production that feeds the beer industry.

MOXEE, Wash. — Flat-bed trucks with high, wooden sideboards and hauling some 150 hop vines apiece line up outside the picking plant at Roy Farms east of Moxee.

In turn, they pull inside and stop at their appointed spots. Workers help the truck drivers attach vines, one-by-one, to hangers on a conveyor of a Dauenhauer picking machine. Vines quickly shoot high overhead on the hangars. Upside down, their foliage falls open, exposing cones that are stripped by hundreds of high-speed mechanical fingers inside the machine.

The picking machine is just one of five stages of harvest that converts hop cones from the field into bales or pellets for processors and brewers within 48 hours.

During September, hop trucks are almost as common as cars on the roads around Moxee, just east of Yakima. The Yakima Valley — notably Moxee, Toppenish and Prosser — is the heart of U.S. hop production, typically producing 80 percent of the nation’s hops. Oregon and Idaho make up the balance.

On the world stage, Germany grows 37 percent of all hops followed by the U.S. at 30 percent, the Czech Republic at 9 percent and China at 6 percent.

In Moxee, harvest runs around the clock from late August through September.

Roy Farms employs about 300 people for harvest. At 3,500 acres, it’s one of the largest hop growers in the nation.

A striking aspect of harvest for a visitor is the many aromas. They can differ depending on hop variety and which step in the process the hops are, producing a woodsy smell or a pine smell.

“Sometimes it can be like citrus,” said Carman McKinney, the company’s manager of food safety and sustainability.

Jim Boyd, director of sales and marketing, has one of the “best noses on the ranch” when it comes to smelling the maturity level of a field, said Michael Roy, hop manager.

“He has the nose that knows,” Roy said. “He knows what customers want in aroma profiles. Customers can have unique preferences.”

Harvest shut down for two days, he said, when Boyd determined a field wasn’t ready. Workers were paid to remain on standby. It’s a cost of doing business during harvest that “demands you have your finger on the pulse of everything that’s going on,” Roy said.

In the field

It all starts in the field, where crews remove 20-foot-tall vines from trellises. Vines, trained by hand in the spring, grow up twine stapled in the ground and extending to trellis wire 20 feet overhead.

A tractor with a low front cutter moves into a row severing the base of the vines and twine.

Lorenzo Gutierrez is one of the workers walking behind the tractor with a machete, cutting vines and twine the tractor missed.

Behind the first tractor, a truck enters the row. The driver puts it in neutral and a tractor behind pushes the truck along as its hydraulic top cutter severs the top of the vines from the trellis wire and the vines fall into the truck bed.

Gutierrez is a third-generation worker on the farm and has worked there 25 years. His father, Narciso, 65, now a field manager, has worked there 49 years and remembers driving wooden pegs to fasten twine, a task now done mechanically.

Others have worked at the farm a long time, including Blas Plazo, tractor driver, who has been there 33 years.

In the plant

Trucks haul vines to the picking plants where the cones are stripped. Stems and leaves of vines are composted and eventually spread back over fields.

Cones go to the drying plant where they are spread 29 inches deep on 32-by-32-foot drying beds. Fourteen large, natural-gas dryers heat air to 125 to 130 degrees that rises through slots in drying-bed floors. In 10 to 12 hours, the heat reduces the hops’ moisture content to about 9 percent. This is done for stabilization and storability, McKinney said.

From drying, cones are conveyed to another building for 24 hours of cooling in piles. Cool air is forced up from the floor to stabilize temperature and moisture and preserve the aromas.

Next, hops are compressed into 200-pound bales and shipped or stored.

Roy Farms is the only grower that also directly processes cones into small pellets to save costs and better preserve aromas and oils for storage of 3 to 5 years, McKinney said. Roy Farms’ “Harvest Fresh” brand pellets are made within 48 hours of leaving the field, she said.

Other growers also make pellets, but from bales.

Bales and pellets are sold to brewers for making beer and to other processors for refinement into concentrated extract, for greater preservation of flavor, before going to breweries.

Technological improvements

The Dauenhauer picking system has been the industry standard since the 1950s but changes are developing. One of Roy Farms’ four processing plants uses a newer Perrault harvester. The high overhead conveyor of hangers is gone. Telescoping forklifts unload trucks and shove the vines up a conveyor belt where machinery chops the vines and separates the cones.

Shorter trellis systems are being tested to reduce overall labor and keep labor needs at a more constant level year-round, Roy said. Experiments include field combines for greater harvest efficiency. Such improvements have to outweigh the loss in yield per acre from shorter trellises, Roy said. Better use of water, fertilizers and pesticides also are being considered.